Question

For the majority of minerals, the streak color obtained when the mineral is scratched against a porcelain plate is ____________. a. likely to be diagnostic only if the mineral is hard enough to scratch porcelain

b. more variable than the color in a hand sample among crystals
c. less variable than the color in a hand sample among crystals d. always dark brown or black

Answer 1

The streak color obtained when a mineral is scratched against a porcelain plate is generally less variable than the color in a hand sample. This is because streak color is the color of the crushed powder of the mineral and tends to be more consistent. Therefore the correct option is c.

Step-by-step explanation:

For the majority of minerals, the streak color obtained when the mineral is scratched against a porcelain plate is c. less variable than the color in a hand sample among crystals. The streak is the color of the powder that a mineral crushes to. Unlike the color of a mineral, which can be impacted by the environment and can vary, the streak color is usually more consistent, regardless of the color of the mineral itself. As such, the streak test, where a mineral is scratched against a porcelain plate, often provides a more accurate method of identification than just color.

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